In a conventional vehicle or work machine, a transmission system transfers torque from an engine or prime mover to a ground-engaging mechanism such as a wheel or track. In a tracked vehicle, for example, a transmission may transfer torque to the tracks to allow the vehicle or machine to move in a forward or reverse direction. If an operator wants to steer the vehicle or machine through a tight turn, the transmission system may include a pivot steer system to do so. To pivot, however, transmission efficiency can be affected by different fluid coupling devices such as a torque converter or hydrostatic steer unit (HSU). These fluid coupling devices may produce losses in the transmission system such that efficiency, i.e., ratio of power into the system versus power out of the system, is reduced. Thus, there is a need to improve efficiency of a transmission system that includes a pivot steer system.